Preparations for the production of metal 8-hydroxy quinolinates and process for utilizing same



United States Patent poration of New Jersey No Drawing. Filed Nov. 30, 1961, Ser. No. 187,999 9 Claims. (Cl. 117-1385) This invention relates to the preparation of non-alkali metal, and particularly insoluble metal S-quinolinolates (8-hydroxyquinolinates), and especially to a process for the in situ deposition of true non-alkali metal 8-quinolinolates from a single treating or impregnating solution, and to antimicrobial compositions containing or giving rise to such metal 8-quinolinolates.

More specifically, the invention relates to processes and compositions utilizing or containing esters of 8-quinolinol for binding non-alkali metals for the purpose of depositing insoluble non-alkali metal 8-quinolinolates in fibrous or porous materials to render them proof against attack by fungi and bacteria and/ or active to reduce the ozone content in their vicinity and thereby protect vegetation subject to attack by ozone, for eliminating undesirable catalytic effects of metals in various materials like lubricating oils, plastic compositions, and the like and for other purposes requiring the conversion of a soluble nonalkali metal compound into a form which is insoluble in aqueous and organic solvents, or substantially so in organic solvents.

The metal salts of S-quinolinol have found extensive use in many industries for the prevention or control of microbial activity. Cellulosic materials such as textiles, wood, paper and cordage have been treated with these compounds to prevent destruction by bacterial and fungal attack. In agriculture, a wide variety of plant diseases, including those of fruits and vegetables, caused by bacteria and fungi have been brought under control by the use of various metal S-quinolinolates. Some of the properties of these salts which have made them outstanding are high anti-microbial activity, low toxicity to human beings, stability to heat, light, and water leaching, as well as lack of odor.

The non-alkali metal 8-quinolinolates, also known as oxinates, are quantitatively insoluble in water and most are practically completely insoluble in many organic solvents. Much effort has been expended to find means for solubilizing these salts so that difiiculties in application could be overcome. Unfortunately, many of the desirable properties of the salts are lost in'the so-called solubilization techniques employed heretofore. In fact, the known solubilizing procedures do not produce true non-alkali metal S-quinolinolates but rather compounds containing other radicals in addition to those of the metal and quinolinol. For example, according to the Uinted States Patent No. 2,745,832, quaternary ammoni um compounds are first caused to form salts with 8-hydroxyquinoline, and these salts are then chemically reacted with non-alkali metal soaps of water-insoluble organic carboxylic acids in an organic solvent solution to yield a metal complex of the quaternary ammonium-8- hydroxyquinoline compound.

Another procedure (US. Patent No, 2,755,280) dissolves metal quinolinolates in polar acid esters of diand tri-carboxylic acids, of which the'free carboxyl groups are of sufficient acidity to form salts with the metals themselves. This process, however, yields a reaction product of the metal quinolinolate with the polar acid ester rather than a true physical solution.

So far as I am aware, all methods heretofore disclosed for the solubilization of insoluble metal quinolinolates involve the use of solubilizing agents which in themselves are reactive to the extent that the metal quinolinolates are caused to undergo chemical conversion to other prod: ucts which are more soluble. However, no reverse reaction takes place, especially under application conditions, for the solubilization techniques employ such elevated reaction temperatures or chemical agents that a reversal to re-form the metal quinolinolates at lower temperatures does not occur.

Although fungicidal activity is still present in these reaction products, many of the other desirable features of true metal quinolinolates have been lost. Among these are their resistance to leaching by water, and insolubility or substantial insolubility of most of the true non-alkali metal oxinates in organic cleaning solvents, which is important in the case of fabrics rendered mildewproof with such salts. Soluble compositions which do not yield true metal quinolinolates will lack permanence or resistance to extraction by solvents and oils.

The primary objective in providing soluble forms of the metal quinolinolates is to achieve complete penetration of the substances to be protected against microbial attack. The importance of this is at once realized, for example, in the mildewproofing of heavy webbing such as is used in parachute harnesses. Surface or partial protection by the use of dispersions of the insoluble metal quinolinolates is unsatisfactory; while treatment in two baths to effect metathetical precipitation of the insoluble compound can lead to failure because of incomplete impregnation.

It is accordingly one of the objects of the present invention to provide a process for the impregnation of fibrous material, such as fabrics, yarn, paper, wood, cordage, leather, and other cellulosic and non-cellulosic materials, in such a manner that under application conditions true metal quinolinolates are deposited in insoluble form from a single treating solution.

It is a further object of the invention to provide antimicrobial preparations and a process of treatment whereby deposition of true insoluble metal 8-quinolinolates can be accomplished regardless of temperature, so that under those use conditions where no heat is or can be applied,

tht metal quinolinolates will still be formed and deposited.

It is also an object of the invention to provide new esters of 8-quinolinol and to utilize their metal binding capacity as well as that of known 8-quinolinol esters in various ways.

Other objects and advantages of the invention will become apparent from the following further description thereof, and the features of novelty will be set forth in the appended claims.

It is well known that the phenolic hydroxyl group of 8-hydroxyquinoline reacts with metal ions to form metal quinolinolates corresponding in composition to one molecule of 8-quinolinol for each valence of the metal, e.g., C H ON'Ag, (C H O'N) Zn, Practically all metals can form such salts, and many are precipitated quantitatively from their other salts in aqueous media by 8-quinolinol at various pHs.

It would be expected that esterification of the phenolic hydroxyl of 8-quinolinol would prevent the formation of metal quinolinolates by reaction with, for example, organic acid salts of the metals. I have however found, quite surprisingly, that even in the complete absence of water, so that hydrolysis of the ester cannot occur, as will be explained hereinafter, the esters of 8-quinolinol react with metal salts to form true metal quinolinolates over a wide temperature range, from such low temperatures as 10 C., to about 200 C., or to a temperature just short of the decomposition temperature, the reaction rate varying with the concentration of reactants, the nature of the acid radicals, the solvents, and the temperature.

It is evident that because of the practically instantaneous reaction between 8-quinolinol and metal salts, it was out of the question to attempt to impregnate fabrics or the like with metal S-quinolinolates by passing the fabric through a solution containing the reacting substances; the insoluble metal oxinate would immediately form and be only superficially deposited. Hence, in order to precipitate, for example, copper-S-hydroxyquinolinate within a fabric, the latter first had to be passed through a bath containing a soluble copper salt, such as copper acetate. After being subjected to the action of squeeze rolls, the fabric was then conducted through a second bath containing a solution of B-hydroxyquinoline in water with a small amount of acetic or other aliphatic acid or any other water-miscible solvent, such as an aliphatic alcohol. This caused a practically immediate precipitation of copper 8-hydroxyquinolinate in the fabric. The fabric was then passed through a drier in which the acetic acid and water were evaporated and also any additional solvent that was employed, such as the alcohol.

One aspect of the present invention is based on my discovery that the metathetical reaction between an ester of S-quinolinol and a metal salt in an organic solvent is an unusually slow one, and in the case of most metal salts, precipitation of the metal oxinate does not begin for a number of hours, in many cases 18 to 24 hours or longer. This aliords adequate time, after a mixture of the reactants in an organic solvent has been prepared, for the solution to be used for impregnating fibrous or porous materials, and for any batch solution to be exhausted before precipitation occurs in the bath. After the impregnated material has passed through the bath and, if desired, through squeeze rolls, it can be allowed to dry at room temperature; after a number of hours, formation of the insoluble oxinate within the impregnated material will occur. In commercial practice, however, it is preferred to heat the treated material in order to speed the deposition of the oxinate and the removal of the solvents together with the formed other product of the reaction.

The present invention accordingly for the first time provides a single bath treatment for the deposition of insoluble metal oxinates within fibrous material and out of an organic solvent.

The observed reaction'is novel, so much so that a new reaction must be postulated which results in the formation of anhydrides even at room temperature along with the metal quinolinolates, in accordance with the following equations:

0 Me(OCgHeN)2 211-0 In the above equations:

Me=metal (monovalent or polyvalent, monovalent being shown in (a) and (b));

R and R'=a hydrocarbon radical, or a substituted hydrocarbon radical, including alkyl groups of 1 to 22. carbon atoms; cycloaliphatic, such as cyclopentyl and e elahexyl; aromatic, like phenyl, hydroxy phenyl, and other substituted phenyl groups; aralkyl, like benzyl, phenylpropyl; and heterocyclic, like f-uryl, etc.

Whereas most of the solubilized compositions heretofore proposed have been prepared by reaction of the various components at elevated temperatures to obtain solution, usually to just below decomposition temperatures, the opposite results are obtained by the present invention; that is, the metal quinolinolat'es form and precipitate even more rapidly at elevated temperatures instead of going into, or remaining in, solution. The ease with which metal salts have been found capable of splitting oxine esters even at low temperatures in the complete absence of water was completely unexpected. The high solubility of the esters in all types of solvents, especially those which are in common use and low in cost, allows for extreme versatility. On the other hand, the ready commercial availability of the salts of metals which are easily soluble in organic solventsbroadens the means and method for preparing metal quinolinolatest I A series of esters of 8-qu'inolinol was prepared by me by conventional procedures. Atn-ong the i'nost common methods employed were the reaction of aeid anhydrides with 8-quinolinol, the reaction of acid chlorides with 8 quinolinol at low temperatures in the presence of pyridine,- or at elevated temperature in the absence of pyridine, and the reaction of organic acid chlorides with alkali metal salts of 8-qt1inolinol in aqueous media. The known tech niques enable the synthesis of many types of esters of 8= quinolinol. The acid component of the ester canbelong to the parafiin or fatty acid series, from the simplest; formic, to extremely long branched and unbranched, chain types, such as acetic, propionic, octoic, and uudecylic and including the saturated acids derived from animal and vegetable oils and fats, and by the hydrogenation of unsaturated acids, such as lauric, myristic, palmitic, steario and arachidic. Unsaturated acids are equally suitable, including those derived from vegetable and animal fats and oils, like undecylenic, oleic, linoleic, linolenic and palmitoleic acids, and also maleic, fumaric, cinriamic; aconitic. Polycarboxylic acids can also be employed; such as oxalic, malonic, succinic, glutaric, sebacic, phthalic and its isomers. Other acids that can be used are benzoic, phenylacetic and phenylpropionic acids, tall oil acids, acidic petroleum products such as naphthenic acid, hydrogenated or partially hydrogenated; and substituted acids such as glycollic, citric, tartaric, salicylic and acetylsalicylic. It is not necessary to employ pure acids; impure acids and mixtures of acids are readily usable. In general, any acid can be used which can form an ester with a phenol, which ester is soluble in some organic solvent.

The metal salts employed can be those whose acid groups are the same as those which form the oxine ester; however, the acids used for the metal salt syntheses can be different from those which form the esters. The use of salts of inorganic acids is possible, e.g., cupric chloride, but salts of organic acids are preferred.

seemed The preparation of the metal quinolinolates can also be accomplished by the use of metal salts derived from the acidic enols of ketones such as 1,3- and 1,4-diketones of, for example, the following types:

R-(fi-CHr-(fi-R, R-fi-CH2CHz-(fi-R quinolinolates can be utilized to react with the esters of S-quinolinol.

The S-quinolinol ester and the metal salt are brought together preferably in solvents which give complete solutions. The ratio of reactants can be stoichiometric, that is, for each metal valence equivalent contained in the metal salt there is added one mole of 8-quinolinol ester equivalent. An excess of either reactant may be used in those applications where the presence of, for example, excess metal salt is desired. Titration of the reactants with each other can be readily run to determine stoichiometric quantities. The esters need not be pure or free from acid, and similarly the metal salts can be used with or without excess acid. In certain applications where an excess of acid may be of advantage, as in the use of stearic acid for imparting water repellency, it has been found that the formation of the metallic quinolinolate is not prevented by its presence.

The reactants, that is, the metal salt and theester of 8-quinolinol, may be brought together in the absence of solvents and physically mixed; or in those instances where the ester is a liquid at moderate temperatures, the reactants can be blended to yield a solution which, on chilling, solidifies. Even in this type of solid composition, the formation of the metal quinolinolate takes place, the rate of reaction being easily varied by the choice of ester and metal salt.

This invention provides still another significant advantage over previous solubilization methods. The solutions of solubilized copper 8-quinolinolate presently available commercially contain, as a maximum, a 10% concentration by weight. Thus, such extra items of cost as freight, containers, storage space, and inefficient solvent handling are incurred compared with the present invention. Esters of S-quinolinol which have an equivalent S-quinolinol content as high as 80% are readily available and metal salts containing high equivalent metal content can serve as the metal source. The advantage is at once seen when it is realized that in the case of copper S-quinolinolate, for example, the copper content is 18.2% and in a 10% equivalent solution there is a mere 1.8% copper concentration. It may be noted that these solutions are further diluted in certain applications, such as the mildewproofing of textiles, but the cost of transporting solutions of 10% strength compared to the equivalent realizable by the present invention represents an economic waste.

A further advantage of this invention lies in the ability to use a mixture of metal salts with a given ester or mixtures of esters so that mixed metal quinolinolates can be prepared simultaneously. For example, it has been reported that the cobalt or manganous S-quinolinolates have proved effective anti-ozonants for the protection of tobacco plants when tobacco shade cloth is treated with them. From a single bath containing both metals as salts and toget-her with various esters of 8-quinolinol, the in situ deposition of both metallic quinolinolates is easily accomplished. In the preservation of canvas products, such as awnings and tenting, the use of mixed metal 6 quinolinolates also becomes possible, certain of these giving protection against mildew and others of the mixture providing resistance to damage from exposure of ultra-violet radiation, or to other microorganisms.

Since the esters of 8-quinolinol can be prepared separately from the metal salts needed to yield the metal quinolinolates, the danger of destruction by oxidation is avoided. No inert atmosphere is required, and the components can be brought together under the mildest of conditions when necessary, to yield the metal quinolinolates.

The present invention has also made possible the preparation of metal quinolinolates, the synthesis of which has not been possible heretofore. For example, mercuric S-quinolinolate of the composition (C H ON) Hg has never been satisfactorily prepared, products of varying composition being obtained prior to the present invention. An example showing the ease of obtaining such a compound by this invention is presented hereinbelow.

Although the present invention is applicable to the esters of the various position isomers of S-quinolinol, such as the 2-, 5-, 6-, and 7-quinolinols, as well as to the esters of their lower alkyl, halo, lower .alkyl-halo, cyano, and amino derivatives, such as 4-met-hyl-8-hydroxy-, 4-methyl-2-hydroxy-, 2-methyl-4-hydroxy-, 5,7- dichloro-, dibromoand diiodo-8-hydroxy-, and S-ethyl- 7-bromo-8-hydroxy-quinolines, 4-cyanoand 7-cyano-8- hydroxy-, and Z-amino-8-hydroxy-quinolines, the 8-quinolinol is the preferred hydroxyqui'noline and the invention will be further described specifically by the use of such compound.

By the processes described hereinbelow, there can be obtained the aluminum, beryllium, magnesium, calcium, strontium, barium, lead, zinc, mercury, tin, iron, nickel, cobalt, manganese, chromium, copper, cadmium, silver, thallium and other non-alkali metal salts of the quinolinols, both in their higher and in their lower oxidation (valence) states.

The speed of the reaction can be controlled not only by way of the temperature but also by other measures. Thus greater dilution of the solutions of the reactants will generally increase the precipitation time, and vice versa; while addition of an alcohol such as a lower alkyl- 01, like ethanol, propanol, isopropanol and butanol, will tend to speed the precipitation, apparently by accelerating the breakdown of the oxine ester.

Hence, by limiting the concentration of the reactants in the organic solvent, the length of time during which the solution remains stable, i.e., does not precipitate the metal oxinate, can be controlled within certain limits. Thus, at a 10% concentration, many of the mixtures of a metal salt of an organic carboxylic acid and of an organic acid ester of hydroxyquinolinol will be stable for about 48 hours.

So far as I am aware, the process described herein is the first to produce many of the metal oxinates in crystalline condition; for example, the copper oxinate. Such crystalline oxinates can be employed as pigments in paints and other coating compositions. Some of the salts like the zinc salts, are fluorescent, and it appears that precipitation from a non-aqueous solvent aids in preserving the fluorescence.

The metal salt and the oxine ester will in many cases react with each other even when mixed in the dry condition to produce the insoluble metal oxinate. Hence, for the preparation of dry stoichiometric mixtures ready for immediate use on solution in a solvent, it is desirable to coat the granules of the metal salt and/or of the oxine ester with a resin or wax or other material in which the reactants are not soluble but which is itself soluble in the impregnating solution. This resin or wax can serve the useful .purpose of rendering the impregnated fabric or other material at least partially water-repellent. If desired, the resin or wax can be leached from the fabric or other material by a suitable solvent after the metal oxinate has been precipitated.

The following examples of carrying out the invention are presented by way of illustration only and not as indicating the limits thereof.

EXAMPLE 1 11.9 gms. S-quinolyl propionate and 23 gms. copper 2-ethylhexoate (8% copper) were dissolved at room temperature in 65 gms. mineral spirits to give a clear solution. In less than 24 hours at room temperature, copper 8-quinolinolate was produce-d and precipitated in the form of needles. Analysis of the precipitate for copper and 8-hydroxyquinoline confirmed the identification in addition to ther distinguishing properties.

An aliquot of the solution, freshly prepared, was heated at 100-125 C. In les than 2 minutes there was practically quantitative precipitation of copper S-quinolinolate.

EXAMPLE 2 In order to prove that the precipitation of the metalloquinolinolate was not preceded by simple hydrolysis of the ester due to the presence of water in any of the reactants, the experiment was repeated with the following precautions observed:

(a) 8-quinolyl propionate Was subjected to high vacuum distillation and the main fraction used. Its boiling point was more than 100 C. higher than that of water under these conditions.

(b) The copper Z-ethylhexoate solution was prepared from anhydrous components (copper acetate and 2-ethylhexoic acid) and then subjected to Water removal by cyclic azeotropic distillation with xylene for a 24-hour period. The xylene was then distilled off.

(c) The solvent, mineral spirits, was dried by chemical means and further purified by fractional distillation.

The preparation of the solution as in Example 1 was carried out using well-dried equipment. Again, copper 8- quinolinolate was obtained in excellent yield after 2 minutes heating at l125 C., and also in less than 24 hours at room temperature.

EXAMPLE 3 11.3 gms. 8-quinolyl propionate and 23 gms. copper 2- ethylhexoate were dissolved in 61.2 gms. xylene at room temperature to give a clear solution. There were then added 3.9 gms. propionic anhydride to act as an acceptor for water. In les than 18 hours at room temperature, copper 8-quinolinolate precipitated in good yield. Elevated temperatures, 110 125 0, caused immediate precipitation.

EXAMPIJE 4 11.9 gms. 8-quinolyl propionate and 23 gms. copper naphthenate (8% copper) were dissolved at room temperature in 65 gms. xylene to give a clear solution on mixing. In less than 24 hours copper S-quinolinolate precipitated. Heating at 110-125 C. caused rapid precipitation.

EXAMPLE 5 The same amounts of reactants as Example 4 were dissolved in 5 gms. of xylene instead of 65 gms. of xylene at room temperature. In less than 18 hours, because of the higher concentration than in Example 4, copper 8- quinolinolate formed in relatively large quantity.

An aliquot of the freshly prepared solution was diluted with mineral spirits to give the equivalent of 1% copper S-quinolinolate solution. Heavy crystallization resulted on standing after 24 hours.

EXAMPLE 6A The presence of a large excess of acid surprisingly does not increase the stability of the ester in the presence of the metal salt, as shown by the following:

36 gms. of S-quinolyl propionate, 38 gms. 2-ethyl hexoic acid, and 69 gms. copper 2-ethylhexoate (8% copper) were mixed at room temperature to give a clear solution. This was then heated at -105 C.; very rapid precipitation of copper S-quinolinolate resulted.

EXAMPLE 6B 12 gms. 8-quinolyl propionate, 24 gms. 2-ethylhexoie acid, 23 gms. copper 2-ethylhexoate (8% copper), and 41 gms. xylene were mixed together at room temperature to give a clear solution. On standing, there gradually deposited copper B-quinolinolate.

EXAMPLE 6C 12 gms. S-quinolyl propionate, 65 gms. propionic acid and 23 gms. copper Z-ethylhexo'ate (8% copper) were mixed together at room temperature to give a clear solution. Even at room temperature, there gradually precipitated copper 8-quinolinolate.

EXAMPLE 6D 12 gms. 8-quinolyl propionate, 12 gms. propionic acid, 20 gms. methyl dihydroabietate and 33 gms. xylene were mixed at room temperature to give a clear solution. Finally, 23 gms. copper 2-ethylhexoate (8% copper) were added. The resultant clear solution gradually deposited copper 8-quinolinolate on standing.

EXAMPLE 7 Some of the commonly employed types of compounds used as plasticizers and water-proofing materials, as in fabric finishing, are esters. It was desirable to determine whether there would be competition in the metal catalyzed ester cleavage between these esters and the oxine ester.

11.9 grns. S-quinolyl propionate were dissolved in 65 gms. polyethylene glycol di2-ethylhexoate at room temperature followed by 23 gms. copper 2-ethylhexoate (8% copper) to give a clear solution. Complete precipitation of copper S-quinolinolate was observed in less than 12 hours.

11.9 gms. -8-quinolyl propionate were dissolved in 65 gms. di-Z-ethylhexyl adipate followed by 23 gms. copper Z-ethylhexoate (8% copper) to give a clear solution at room temperature. Heavy crystallization of copper 8- quinolinolate resulted on standing at room temperature in less than 18 hours.

11.9 gms. 8-quinolyl propionate, 55 gms. di-2-ethylhexyl adipate, 10 gms. methyl dihydroabietate, and 23 gms. copper Z-ethylhexoate gave 'a clear solution on mixing at room temperature. Very heavy precipitation was observed, copper 8-quinolinolate having formed in less than 12 hours.

Additional experiments were run with a wide variety of the commonly used plasticizer-type esters. These included esters of furnaric, maleic, adipic, citric, sebacic, phthalic, azelaic, oleic, 2-ethylhexoic, stearic, glycolic, and other acids as well as acid mixtures obtained from fats and oils of natural origin. The alcohol components of these esters ranged from the butyl to tridecyl, and included cyclic and alicyclic alcohols. In no case was there any interference with the metal-catalyzed cleavage of the oxine ester to yield the copper S-quinolinolate. Both *dlltltfi and concentrated solutions of the oxine esters and the metal salts yielded the metallo-quinolinolate under such mild conditions as room temperatures, or at elevated temperatures, in the presence of small or large concentrations of the plasticizer-type esters 'as such or in mixtures with each other.

EXAMPLE 8 Although it had been determined that the neutral esters Were Without influence on the metal-catalyzed cleavage of the oxine esters, and the presence of varying amounts of unbound acids similarly did not prevent metal quinolinolate formation, runs were made to study the effect of acidic esters.

A solution of 12 gms. S-quinolyl propionate, 65 gms.

ethyl 2,2-dimethyl-4,-cyclohexane-dione oarboxylate was prepared, using gentle warming. Then, 23 gms. copper 2-ethylhexoate (8% copper) were added. In less than 24 hours the viscous solution deposited copper 8-quinolinolate.

10 gms. of the above freshly prepared solution were diluted with 70 gms. mineral spirits and 20 gms. xylene to give a clear solution. On standing overnight, heavy precipitation of copper 8-quinolinolate was evident.

30 gms. 8-quinolyl propionate and 60 gms. copper octoate (8% copper) were dissolved in 150 gms. decyl acetoacetate at room temperature to give a clear solution. In 24 hours heavy crystallization of copper 8-quinolinolate was noted.

9 gms. copper di-(ethyl acetoacetate) and 12 gms. 8- quinolyl propionate were added to 1 liter mineral spirits and heated at 70 C. to give a clear solution. In less than minutes copper 8-quinolinolate precipitated.

12 gms. 8-quinolyl propionate, 65 gms. n-decyl benzoylacetate and 23 gms. copper 2-ethylhexoate (8% copper) were mixed at room temperature to give a clear solution. In 24 hours there was gradual precipitation of copper 8- quinolinolate.

12 gms. 8-quin0lyl propionate, 23 gms. copper 2- ethylhexoate (8% copper) and 10 gms. ethyl acetoacetate were mixed together at room temperature. In 24 hours heavy precipitation of copper 8-quinolinolate resulted.

EXAMPLE 9 18.2 gms. S-Iauroyloxyquinoline and 23 gms. copper 2-ethylhexoate (8% copper) were mixed at room temperature to give a clear solution. On heating at 90-100 C., rapid precipitation of the copper 8-quino1inolate occurred. 50 ml. of xylene were added and the mixture heated at 100 C.; no solution took place. Pure copper 8-quinolinolate was easily isolated.

EXAMPLE 10 14 gms. S-quinolyl benzoate were dissolved in 70 gms. xylene by warming. Next, 22 gms. copper 2-ethylhexoate (8% copper) were added. On heating at 95 C., heavy precipitation of copper 8-quinolinola-te resulted.

EXAMPLE 1 1 38 gms. S-quinolyl stearate, 46 gms. copper 2-ethylhexoate (8% copper) and 116 gms. mineral spirits were mixed at room temperature to give 'a clear solution. In one-half hour at 95 0, heavy crystallization of copper 8-quinolinolate was observed.

51 gms. 8-quinolyl stearate, 46 gms. copper 2-ethylhexoate (8% copper) and 100 gms. xylene were mixed at room temperature to give a clear solution. On heating at 95 C. in less than 15 minutes, heavy precipitation of copper 8-quinolinolate occurred. When a freshly prepared solution was diluted with mineral spirits to a final concentration of the equivalent of 2% copper 8- quinolinolate, heating at 95 C. caused rapid precipitation of the copper oxinate. Even standing at room temperature was sufiicient for gradual reaction, the deposition of copper S-quinolinolate taking place within 24 hours.

EXAMPLE 12 A solution of 16 g. S-quinolyl 2-ethylhexoate in 40 g. 2-ethylhexoic acid was mixed with 23 g. copper 2-ethylhexoate (8% copper) to give a clear solution. On standing for a period of several days at room temperature, gradual precipitation of copper-S-quinolinolate occurred. A ten-fold dilution with mineral spirits showed the same behavior.

A solution of 16 g. 8-quinolyl 2-ethylhexoate in 10 g. 2-ethylhexoic acid was mixed with 23 g. copper 2-ethylhexoate (8% copper) to give a clear solution at room temperature. It gradually deposited copper 8-quinolinolate on standing at room temperature. Heating at 95 C. caused rapid precipitation.

A solution of 16 g. S-quinolyl Z-ethylhxoate and 46 g. copper 2-ethylhexoate (8% copper) in 138 g. mineral spirits was obtained on mixing at room temperature. Heating at C. caused precipitation of the copper oxinate in a short period of time, i.e., a few minutes.

In contrast to the above solutions which remained clear long enough at room temperature for application to be made, as will be shown, the following was run to illustrate the difference in behavior with 8-hydroxyquinoline.

8.2 gms. 8-hydroxyquinoline were dissolved in 40 gms. 2-ethylhexoic acid with gentle warming. The clear solution was then cooled to room temperature. There were then added 23 gms. copper Z-ethylhexoate (8% copper). Immediate precipitation of copper S-quinolinolate took place on mixing.

In addition to the esters of oxine enumerated in the examples, there were used the phthalate, maleate, oleate, furoate, citrate, naphthenate, sebacate, butyrate, mixed fatty acid esters with palmitic and stearic acids, linoleic and linolenic acids, tall oil acids, malonate, phenylacetate, cinnamate, para-nitrobenzoate, and other organic carboxylic acids. In no instance was there failure of cleavage in the presence of soluble copper salts to yield the copper oxinate. Among the copper salts utilized were the propionate, naphthenate, oleate, resinate (salts of rosin acids), 2-ethylhexoate, stearate, ethyl acet-oacetate, ethyl benzoylacetate, laurate, linoleate, succinate, phthalate, and decanoate.

An interesting and unexpected result was obtained on fusing two components, the oxine ester and copper salt.

25.4 gms. 8-qu-inolyl stearate and 11.7 gms. copper 2-ethylhexoate (15.5% copper) were mixed as follows: the ester was melted by heating. The copper 2-ethylhexoate was stirred in rapidly, the temperature being maintained at 40-45 C. for 23 minutes. The clear molten mass was poured on to a cool glass surface and solidified. The product, readily pulverized, gave a clear solution in mineral spirits and also in benzene. On heating the solution in either solvent at 80 0, rapid precipitation of the copper S-quinolinate was observed. The solid, which initially gave perfectly clear solutions, gradually converted in the solid state to copper 8-quinolinolate, even though stored under dry conditions at ambient temperatures. There was a change in color to the typical copper oxinate, solubility in organic solvents was lost, and analysis confirmed the conversion. This illustrates the ability of the oxine ester and the copper salts to interact to the complete exclusion of a solvent medium. Evidently, the release of the oxine from its ester provides for a reaction-medium, along with the removal of the copper from its salt.

EXAMPLE 13 12.5 gms. 8-quinolyl Z-ethylhexoate and 12.5 gms. zinc naphthenate (8% zinc) were dissolved in 25 gms. mineral spirits at room temperature to give a clear light amber solution. On standing at room temperature, in less than 18 hours a voluminous zinc oxinate precipitated. It failed to dissolve on heating.

A sample of the above freshly prepared solution was heated to C. In less than two minutes, a very rapid color change and heavy precipitation of zinc oxinate took place.

EXAMPLE 14 14 gms. 8-quinolyl stearate were dissolved in 24 gms. mineral spirits with gentle heating. The solution was cooled to room temperature and 12.5 gms. zinc naphthenate (8% zinc) were added. On heating at 110 C., there was complete precipitation of zinc oxinate in less than 1 minute. Further heating even at higher tempera tures failed to effect solution of the precipitate.

EXAMPLE 15 7.2 gms. S-quinolyl benzoate were dissolved in 80 gms.

xylene at room temperatures. There were then added 12.5 gms. zinc naphthenate (8% zinc), to give a clear solution. This was heated at 110 C., and in minutes a very intense yellow color developed, typical of zinc oxinate. This was soon followed by the heavy precipitation of zinc oxinate.

The use of other soluble salts of zinc, such as the oleate, 2-ethylhexoate, stearate, propionate, and palmitate gave similar results. Other solvents were employed, such as ethers (diethyl ether, di-isopropyl ether, phenyl methyl ether), ketones (acetone, methyl isobutyl ketone, methyl n-propyl ketone, cyclohexanone), aromatic hydrocarbons (benzene, toluene, xylene), aliphatic hydrocarbons (petroleum fractions), and other inert organic solvents (trichlorethylene, tetrachlorethylene, tetrachlorethan-e. chloroform, carbon tetrachloride, chlorbenzene), with no interference with zinc S-quinolinolate formation. A wide variety of esters of 8-hydroxyquinoline were also catalytically split by the zinc salts to yield the zinc quinolinolate. An excess of either reactant was employed, it not being necessary to employ stoichiometric amounts. In many applications, such as the mildewproofing of cordage or canvas products, it is desirable to have an excess of the zinc salt present, e.g., the zinc naphthenate, over the zinc quinolinolate.

In the use of my improved process for the incorporation of metalloquinolinolates in paints which dry in the sense of oxidation, it becomes necessary to limit the amount of oxine ester employed compared to the metal salt, so that the quantity of metal salt needed as the drier in the paint system will remain the same to catalyze the air oxidation process rather than react with the oxine ester completely. This is easily accomplished by simple calculation, the stoichiometry of the reactions being given above.

For illustrative purposes, the following reaction is presented by way of example:

It is seen that 542 parts by weight (2 moles) of 8- quinolyl 2-ethylhexoate will react with 349.6 parts by weight '(1 mole) of zinc Z-et-hylhexoate to yield 351.6 parts by weight (1 mole) of zinc quinolinolate. Thus the quantity of metal salt desired as a drier can easily be calculated beyond that needed for reaction with the oxine ester.

EXAMPLE 16 68.5 gms. S-quinolyl propionate were dissolved in 515 gms. mineral spirits with gentle warming. There were then added 167 gms. cobalt naphthenate (6% cobalt). In less than 1 minute at 1.15 C, the solution gave rise to a very heavy precipitate of cobalt quinolinolate. At room temperature, the freshly prepared solution showed precipitation of cobalt quinolinolate within one-half hour.

EXAMPLE 17 137 gms. 8-quinolyl Z-ethylhexoate were dissolved in 200 gms. mineral spirits at room temperature. Upon the addition of 167 gms. cobalt naphthenate (6% cobalt) and heating at 100 C., cobalt quinolinolate formed in less than two minutes as an insoluble precipitate in large amount.

I 2 EXAMPLE 18 In order that the reaction may take place between the oxine ester and the metal salt, it is not necessary that the resultant metalloquinolinolate be insoluble and precipita-te from the solution. A most striking experimental result was obtained by using aluminum Z-ethylhexoa-te which illustrates this.

20 gms. of aluminum 2-ethlyhexoate were added to 500 ml. mineral spirits at room temperature. There were then added 55 gms. 8-quinolyl Z-ethyl'hexoate. On heating at l=l0 C., a rigid gel formed in the first two minutes. This was then followed rapidly by the formation of the aluminum quinolinolate typified by color change and release of the gel to a non-viscous liquid. No product precipitated although a turbidity was evident. This reaction was complete in 5 minutes. On further heating at 110 C., for 1 hour, the mixture remained unchanged. By contrast, 20 gms. of aluminum Z-ethylhexoate in 500 ml. of mineral spirits, without any ester, on being heated at 110 (1., gave a rigid gel in two minutes, but further heating at 110 C. for an additional hour was without influence on the gel.

Additional evidence that the loss of gel structure formed initially by the aluminum octoate is due to the capture of the aluminum by the oxine released from the ester has been obtained. 20 gms. of aluminum octoate, 36 gms. Z-ethylhexoic acid, and 500 ml. mineral spirits were heated to 110 C. Again, within 2 minutes, a rigid gel formed and persisted for the next hour at 110 C., indicating that the Z-ethylhexoic acid is without influence on the gel.

This interesting phenomenon affords another useful application of the oxine esters for reaction with metals. In industrial processes, troublesome gels are sometimes encountered which interfere seriously with such operations as settling, filtration, or clarification. Such a problem has been encountered especiaily in handling oils. It has been demonstrated repeatedly that metallic ions are largely responsible together lVVI'th relatively high moiecular weight anions. The addition of the esterified oxine causes a prompt binding of the metal ions with breakdown of the gel.

It has been reported that the presence of metals accelerates the air oxidation of many types of organic materials such as oils for lubrication. The addition of oxine esters to form the corresponding metalloquinolinolate removes the metal, permitting the maintenance of metal-free lubrication.

EXAMPLE l9 10.6 gms. magnesium stearate were dissolved in ml. xylene with gentle warming. Then 8.4 gms. of 8- quinolyl propionate were added, which dissolved rapidly. The resultant solution slowly deposited magnesium oxinate at room temperature and very rapidly at with the prior development of an intense lemon yellow color. Further heating failed to dissolve the precipitate.

EXAMPLE 20 In a similar procedure using tallates, ricinoleates, naphthenates, octoates, oleates and other salts of such metals as cerium, zirconium, ferric iron, lead, calcium, barium, mercuric mercury, manganese, cadmium, nickel, silver, bismuth and tin, the corresponding metalloquino- Iinolates readily formed. In some instances there was rapid precipitation on heating: In other cases where the metalloquinolinolate was soluble in the solvents employed, a marked color change was noted.

A solution was prepared at room temperature from 10 gms. mercuric Z-ethylhexoate (37% Hg), 10 g. 8- quinolyl Z-ethylhexoate and 60 gms. mineral spirits. A clear, light yellow color was noted. On heating, at C. for less than 2 minutes, a deep red color followed by the precipitation of mercuric oxinate was observed. The solution which remained at room tem- 13 perat'ure gave a further quantity of the same product in 72 hours.

The substitution of mercuric naphthenate (25% Hg) for the octoate gave the same results.

In the application of this process for the mildewproofing of cotton fabric, the following procedure was conducted: A solution was prepared using 8- uinolyl 2- ethylhexoate and copper octoate in mineral spirits to give the equivalent of 2% copper 8-quinolino1ate. At a pick-up of 50% by weight of solution, using conventional equipment, the fabric was found after drying to contain 1% copper 8-quinolinola-te. This was not extractable with organic solvents or water, and on burial in soil previously inoculated with cellulose destroying fungi, no loss in tensile strength or fungal attack was observed over a period of twelve weeks. Existing plant equipment can be used without modification for carrying out the impregnation, which is one of the advantages of my process.

EXAMPLE 21 50 gms. 8-quinolyl benzoate, 100 gms. calcium naphthenate (4% calcium) and 750 gms. mineral spirits were heated to give a clear solution. Within 2 minutes at temperatures above 100 C. complete precipitation of calcium oxinate resulted.

EXAMPLE 22 16.7 gms. zirconium naphthenate (6% Zr), 8.9 gms. S-quinolyl propionate and 47 gms. mineral spirits dissolved on gentle warming to give a light greenish yellow solution. In less than 1 minute at 135 C. a rapid color change occurred denoting the formation of zirconium oxinate. 7

EXAMPLE 23 EXAMPLE 24 16.7 gms. ceric naphthenate (6% cerium), 5.8 gms. 8-quinolyl propionate and 29 gms. mineral spirits gave a clear solution on mixing. Heating at 105 C. gave heavy precipitation of ceric oxinate.

EXAMPLE 25 25.8 gms. commercial copper tallate (7% Cu), 16 gms. 8-quinolyl 2-ethylhexoate, and 58 gms. mineral spirits were mixed at room temperature to give a clear deep green solution. In less than two minutes of heating at 125 C., the initially clear solution became a thick paste due to the precipitation of copper S-quinolinolate.

EXAMPLE 26 gms. lead octoate (24% Pb), 7.0 gms. 8-quinolyl octoate and 80 gms. mineral spirits were mixed at room temperatures to give a'clear solution. An aliquot was heated to boiling for a few minutes. A very sharp color change denoted the liberation of oxine from the esterified compound and consequent lead oxinate formation. The remainder of the initial solution showed the same transformation at room temperatures in 2448 hours.

The use of other solvents, such as benzene or xylene, gave identical results. Lead naphthenate (commercial), containing 24% lead, also underwent reaction in the same way with the esterified oxine.

EXAMPLE 27 32 ml. of manganese naphthenatae (commercial), containing 6% manganese, 35 ml. of S-qinolyl 2-ethylhexoate and 200 m1. of mineral spirits were mixed at room temperature to give a clear solution. Heating at 125 C. for '2-5 minutes caused a very marked color change, again 14 due to the release of oxine from the ester and formation of the oxinate.

EXAMPLE 28 The oxine esters can be employed also for protecting various coatings for wires, and particularly for underground cables, against fungal and bacterial attack. Thus, in a known wire-coating composition composed of linseed oil, zinc oxide, and neoprene rubber, which is thermocured at about 290 F., there may be added a small proportion, say about to A% (based on the weight of the linseed oil) of the oxine ester, such as the stearate, oleate or 2-ethylhexoate (octoate), the oxine ester will bind the metal of the metal compound employed as the catalyst and thus form the antifungal and antibacterial metal oxinate.

The presence of amines does not interfere with the precipitation of the metal oxinate. Thus diethylamines, ethanolamine, di-2-ethylhexylamine and aniline do not prevent the reaction between the copper compound and the oxine ester, as is shown by way of illustration by the following:

EXAMPLE 29 46 gms. cop-per octoate (containing 8% copper), 33 gms. 8-quinolyl 2-ethylhexoate, 23 gms. 2-ethyl hexoic acid, 60 gms. diethyl amine and 30 gms. of mineral spirits were mixed at room temperature to give a clear solution. On heating the solution for 1530 minutes at -100 C., copper 8-quinolinolate precipitated. An aliquot of the unheated solution, allowed to stand at room temperature, deposited copper 8-quinolinolate in 24 hours.

Metal alcoholates and metal phenates can be employed in the above example to yield the metal 8-hydroxyquinolinates. Examples of these starting compounds are copper ethylate and copper and calcium phenates. Copper ammonium salts, and also copper amino complexes in non-aqueous solvents, will precipitate the copper oxinate on reaction with the oxine ester. Organic metal compounds that are not strictly salts but which are soluble in a solvent in which the oxine ester is also soluble may also be used, such as calcium and magnesium di-(lower alkyl) malonate esters, whose formulas can be written as follows:

alkyl. 0 O C C :Me

alkyl. 0 O 0 wherein alkyl stands for lower alkyl, such as methyl, ethyl, propyl, butyl, etc., while Me represents the metal, preferably calcium and magnesium. Various metal enolates can be employed, such as copper acetyl acetone, and also salts, preferably the copper salts of beta-ketoesters, such as methyl 3-keto-butyrate and ethyl 3-keto hexoate and octoate and other lower alkyl keto-esters.

It will be understood that in place of the specific esters of oxine named in the above examples, other esters, and also the corresponding esters and other esters of derivatives of oxine, such as the propionic, 2-ethylhexoic and undecylenic acid esters of 5,7-dichloro-8-hydroxyquinoline, can be employed. The preferred hyd-roxyquinoline esters are generally those of 2-ethylhexoic acid, naphthenic acid, and the acids obtainable from animal and vegetable fats and oils, particularly oleic and stearic acids.

Benzene, xylene, and toluene have a slight solvent action on certain of the metal 8-quinolinolates, while mineral spirits and other saturated aliphatic hydrocarbons generally have the least solvent action. Aluminum forms an oxinate which is quite soluble in organic solvents, but oxinate of this metal as well as of the other non-alkali metals is quite insoluble in water.

Comparison with a commercial preparation containing a so-called solubilized copper oxinate in a concentration of 10% calculated as copper oxinate, which did not precipitate copper oxinate on heating, or on dilution with mineral spirits, or on standing at room temperature for several months, showed that cotton webbing, such as is used for parachute harnesses and knapsack straps, absorbed about one-third less of the fungicide (on the basis of the copper content) when treated with such preparation than when treated with the reaction mixture of copper Z-ethylhexoate and the Z-ethylhexoic acid ester of oxine in accordance with the present invention.

According to the Rose method of analysis for copper 8-quinolinolate, which is the method of analysis described in many Government specifications for fabrics mildewproofed with this fungicide, a fabric which has been treated for depositing this salt therein is heated with 10% sulfuric acid to 95 C. and the liquid then decanted. This treatment is repeated twice, and the three extracts are then combined, neutralized, and then tested for the content of copper S-quinolinolate in the combined extracts. This procedure will remove all of the salt from a fabric treated either "by the known two-bath method wherein the fabric is first passed through a solution containing a soluble copper salt and then through a solution of S-hydroxyquinoline, and/or by the so-called single bath method wherein there is employed a solu-bilized copper 8- quinolinolate. It is also the method employed in testing fabrics which have been treated with a dispersion of copper 8-quinolinolate.

In all these known methods of treatment, the extractions remove 100% of the copper compound in the fabric, but when the same test is applied to fabrics treated to deposit copper S-quinolinolate therein in accordance with the present invention, only about of the copper salt is extracted, where 1% of the salt has been deposited, as is required by certain Government specifications. Heating with 10% sulfuric acid for a much longer time is required to remove substantially all of the copper salt from tfabric treated in accordance with my invention. This difference is probably due to the fact that in my process, by reason of the fact that the solution contains both re- :acting substances when it is absonbed by the fibers, precipitation occurs uniformly throughout the interior of the fibers, as well as upon their surfaces. This is to be distinguished from a two-bath treament in which the fibers are initially impregnated with, for example, copper acetate, and are then treated with a solution of 8- hydroxyquinoline. In such case, since precipitation occurs immediately, the fibers become coated with the in- :soluble copper 8-quinolinolate and this coating bars access of the S-hydroxyquinoline to the interior of the fiber.

It may be that the simultaneous formation of the anhydride when the metal compound is in the form of a carboxylic acid salt, in some way affects or modifies the nature of the deposition of the copper oxinate and possibly other oxinates, and the manner in which they are :absorbed or adsorbed by the fibers. The extraction test establishes a far greater permanence of the deposit effected by the present invention than is obtainable by prior protcedures.

It will be understood from the foregoing that while in :my preferred treating process I employ materials of a fibrous or porous nature, such as those specifically named Ihereina bove, my process is applicable also to the treat- :ment of more or less nonporous materials by providing .them superficially with an anti-fungal coating.

Where a paint or other coating composition contains a metal salt dissolved in the vehicle, the composition can be rendered mildew-proof either by the direct addition of an oxine ester to the paint by the manufacturer, or the ester can be supplied to the purchaser of the paint to be added immediately before use of the paint or other coating composition. Where the coating composition does not contain a non-alkali metal salt in solution, the salt can be added to the composition by the manufacturer or by the user just prior to use, along with the oxine ester. The amount of oxine ester that is added, with or without the added metal salt, need be no more than 1% of the total weight of the paint, a quantity ranging between to by weight of the coating composition being usually sufificient. v

For protecting lubricating oils, it is preferred to employ the oxine esters of saturated acids, such as the 2- ethylhexoic, myristic, palmitic, stearic and other higher molecular weight fatty acids which are not subject to oxidation. The amount of the ester should be that sufficient to bind the metal compounds normally occurring in lubricating oils and will ordinarily amount to no more than about /,,0% to 1 of the weight of the oil.

The anhydrides produced in the above-described reactions are usually of benefit in the process, since they are capable of reacting with cellulosic fibers to produce, for example, cellulose esters which are more water-repellent than the original cellulosic fabric or other material. My process accordingly reduces or even eliminates the need for treatment of a fabric to render it water-repellent, as in the case of tent material, parachutes, and the like.

It will be seen from the foregoing that the present invention provides a process whereby true non-alkali metal S-quinolinolates can be precipitated out of a single treating solution by taking advantage of the fact that the re action between the metal salt, preferably of an organic acid, and the ester of 8-quinolinol proceeds so slowly that precipitation will not ordinarily occur for quite a number of hours at room temperature, so that the complete batch of a mixture of the reactants can be exhausted in impregnating a fibrous or porous material before precipitation sets in within the fibers or the interstices of the material being treated. Once the impregnation has taken place, the precipitation of the metal S-quinolinolates (oxine) can be accelerated by heating to any elevated temperature below the decomposition point; usually temperatures of to C. will be adequate. The procedure of the present invention has, in addition to the advantages above mentioned, the further advantage that the oxine ester is usually soluble in all of the solvents in which the metal salt is soluble, whereas the presolubilized mixtures of the prior art are usually limited in their solubility, for example, to solubility in xylene or mineral spirits. As shown by the foregoing, the present process can be conducted even without the use of any solvent.

I claim:

1. The method of preparing non-alkali metal S-quinolinolates which comprises reacting an ester of 8-quinolinol with a salt of a non-alkali metal in the absence of sufficient water to cause substantial hydrolysis of the ester before it reacts with the metal salt.

2. The method according to claim 1 wherein the reaction is carried out in the presence of an organic solvent.

3. The method according to claim 2 wherein the ester group of the 8-quinolinol ester is derived from an organic carboxylic acid.

4. The method according to claim 3 wherein the salt is a metal salt of an organic carboxylic acid.

5. The method according to claim 4 wherein the ester group and the metal salt are derived from aliphatic or cycloaliphatic carboxylic acids.

6. The method according to claim 5 wherein the metal of said metal salt is aluminum, beryllium, magnesium, calcuim, strontium, barium, lead, zinc, mercury, tin, iron, nickel, cobalt, manganese, chromium, copper, cadmium, silver, thallium, zirconium or cerium.

7. The method according to claim 6 wherein the ester group is propionate, Z-ethyl hexoate, lauryloxy, stearate or benzoate and the metal salt is the metal 2-ethyl hexoate, naphthenate or stearate.

3. The method according to claim 7 wherein the ester is 8quinol'yl 2-ethyl hexoate and the metal salt is copper Z-ethyl hexoate.

9 The method for incorporating a metal 8-quinolinolate Within a fibrous or porous material which comprises dissolving an ester of 8-quinolinol and a salt of a non-alkali metal in an organic solvent in the absence of suflicient Water to cause substantial hydrolysis of the ester before it reacts with the metal salt, and passing said fibrous or porous material through the solution so obtained before a substantial amount of metal quinolinolate is formed and heating the so treated material to accelerate the formation of said metal quinolinolate within the material.

References Cited by the Examiner UNITED STATES PATENTS 2,030,033 2/1936 McConnell 44-63 2,255,597 9/1941 Downing et al. 252-515 X 2,298,640 10/ 1942 Prutton 252-515 X 2,363,778 11/1944 Pederson 252-51 X 2,372,588 3/1945 Larsen et al. 252-515 X 2,381,863 8/ 1945 Benignus.

2,523,114 9/1950 Hawley 117-1385 2,526,948 10/1950 Himel 117-138.5 2,608,556 8/1952 Kalberg.

2,666,058 1/ 1954 Neher 167-33 X 2,745,832 /1956 Fath et al 260-270 2,755,280 7/1956 Feigin et al 260-270 2,799,615 7/1957 Heymans et al 167-33 1 8 2,895,837 7/1959 Bilger et al. 106-18 2,991,183 7/1961 Lederer et al. 106-18 2,979,434 4/1961 Santmyer 167-22 3,002,882 10/1961 Andel 167-22 3,017,362 1/1962 Cyba 252-515 3,031,402 4/ 1962 Nelson 252-515 OTHER REFERENCES Blair et al., Chemical Abstracts, vol. (1956), page 1517.

Martell et al., Chemistry of the Metal Cholate Compounds, pub. by Prentice-Hall Inc. (1956), page 511.

Phillips, Chemical Reviews, vol. 56 (February-June 1956), page 272, Reactions of 8-Quinolinol With Metal Ions.

Salesin et al., Talanta, vol. 4 (March 1960) pages to 77, Precifin. of Metal S-Hydroxyquinolinates.

Seiler et al., Chemical Abstracts, vol. 49 (1955), page 8954.

Vogt, Chemisches Zentralblatt, vol. 116 (October- December 1945), Darstellung-Oxychinolin Fettsaureestern. ,4

DANIEL E. WYMAN, Primary Examiner.

JULIUS GR'EENWALD, Examiner.

P. C. BAKER, W. H. CANNON, Assistant Examiners. 

9. THE METHOD FOR INCORPORATING A METAL 8-QUINOLINOLTE WITHIN A FIBROUS OR POROUS MATERIAL WHICH COMPRISES DISSOLVING AN ESTER OF 8-QUINOLINOL AND A SALT OF A NON-ALKALI METAL IN AN ORGANIC SOLVENT IN THE ABSENCE OF SUFFICIENT WATER TO CAUSE SUBSTANTIAL HYDROLYSIS OF THE ESTER BEFORE IT REACTS WITH THE METAL SALT, AND PASSING SAID FIBROUS OR POROUS MATERIAL THROUGH THE SOLUTION SO OBTAINED BEFORE A SUBSTANTIAL AMOUNT OF METAL QUINOLINOLATE IS FORMED AND HEATING THE SO TREATED MATERIAL TO ACCELERATE THE FORMATION OF SAID METAL QUINOLINOLATE WITHIN THE MATERIAL. 